We are working on three groups of fungi parasitic on mosquitoes. (1) Coelomomyces. We plan to: a) complete the taxonomic monograph on this genus by the end of 1975; b) to find out how the fungus enters its host and; c) to get another species of Coelomomyces which attacks a mosquito of health importance in culture in its host as we have done with C. punctatus in Anopheles quadrimaculatus. (2) Lagenidium giganteum. This fungus is a very effective killer of mosquitoes in the laboratory. Its effectiveness in the field is hampered by the fact that the sporangia appear to lose their ability to form good zoospores in artificial culture. We are working on culture methods by which the inoculum retains its infective potential. The zygotes in Lagenidium are formed only in dead larvae and not in artificial culture so far. The zygotes are resistant to drying and retain their infecting power. If zygotes could be produced in large quantity in artificial culture, the value of Lagenidium in field work would be more practical. (3) Culicinomyces which can be grown axenically appears to be the most effective of our group and field tests are in progress to test its potential for controlling mosquitoes.